1. Field of the Invention
The present invention relates to a power steering apparatus.
2. Description of the Related Art
In a conventional power steering apparatus, a rack shaft is supported by a gear housing so as to be linearly movable, and a pinion connected to a steering shaft meshes with rack teeth of the rack shaft. A cap is screwed in the vicinity of a crossing portion of the rack shaft of the gear housing and the pinion, and the rack shaft is supported from its back to the cap by a rack guide backed up via a spring, so that the rack teeth of the rack shaft are forcibly caused to mesh with the pinion.
In the conventional art, however, it is difficult to suitably adjust the spring force of the spring for backing up the rack guide, and steering operation is thereby diminished because of an increase in operation resistance of the rack shaft. Also, there is a constant clearance or gap between the rack guide and the cap. For this reason, when a reaction force which is imparted on a road wheel from a road surface acts on the rack shaft, the rack guide compresses and displaces the spring in the range of the clearance, and the rack guide strikes the cap to generate striking or chattering noises.
An object of the present invention is to arrange the meshing between rack teeth of a rack shaft and a pinion appropriately with a structure where striking noises are not generated at a rack supporting portion of a power steering apparatus.
The present invention is a power steering apparatus where a rack shaft is supported by a gear housing so as to be linearly movable, and a pinion connected to a steering shaft is caused to mesh with rack teeth of the rack shaft, wherein the rack shaft is supported by the gear housing via a rack adapter. The rack adapter comprises an outer peripheral supporting portion supported by the gear housing and an inner peripheral supporting portion supporting the rack shaft. A supporting center of the inner peripheral supporting portion is positioned to be eccentric with respect to a supporting center of the outer peripheral supporting portion. The mounting angle position of the rack adapter relative to the gear housing about the supporting center of the outer peripheral supporting portion of the pinion adapter is arranged to be adjustable.